Air Microflora of Lecture Theater One (lt1) University of Ilorin

This study evaluated the airborne microbial flora in Lecture Theatre 1 (LT1) of the University of Ilorin through weekly passive settling plate sampling over five weeks, exposing nutrient agar (for bacteria) and potato dextrose agar (for fungi) plates for 10 minutes at random locations. Plates were incubated at 37 °C (24–48 h) and 25 °C (48–72 h), respectively, and isolates were purified and identified by colonial morphology, Gram staining, and standard biochemical tests (bacteria) or macroscopic/microscopic features (fungi). In total, 20 bacterial and 8 fungal isolates were recovered. The bacterial isolates were: Streptococcus pyogenes, Streptococcus equi, Streptococcus sanguis, Streptococcus salivarius, Staphylococcus epidermidis, Streptococcus equinus, Streptococcus faecalis, Staphylococcus saprophyticus, Staphylococcus salivarius, Streptococcus aureus, Bacillus subtilis, Micrococcus varians, Peptococcus activus, Bacillus megaterium, Bacillus badius, Citrobacter freundii, Pediococcus pentosaceus, Acetobacter aceti, Pseudomonas aeruginosa, Flavobacterium breve, while fungal isolates were: Aspergillus clavatus, Penicillium digitatum, Penicillium variabile, Aspergillus fumigatus, Penicillium italicum, Chrysomilia sitophila, Penicillium commune, Rhizopus stolonifera. The detection of opportunistic pathogens such as S. aureus and A. fumigatus highlights a potential health risk for theatre users, and the passive method likely underestimates true bioaerosol concentrations.